The present invention relates to an electrophotographic photoreceptor that has a surface layer with improved hardness and which will not produce any blurred image even if it is subjected to cyclic use.
It has recently been proposed that a photoconductive layer made of a silicon-based material (also known as amorphous silicon) be provided on a support to make an electrophotographic photoreceptor. A photoreceptor using a silicon-based photoconductive layer has advantages with respect to mechanical strength, panchromatic color rendition and sensitivity to the long-wavelength light over photoreceptors that employ inorganic photoconductive materials such as Se, tri-Se, ZnO and CdS, or a variety of organic photoconductive materials. However, when a copy obtained with photoreceptor using a silicon-based photoconductive layer is left to stand in air, especially in a hot and humid atmosphere, the image on the copy will become blurred. In addition, when the photoreceptor is rubbed with a drum cleaning blade or a paper stripping finger during the electrophotographic process, the surface state of the photoreceptor is altered to produce an image having surface defects as manifested by white streaks. In order to eliminate these problems, proposals have been made in which surface layers having various compositions such as Si:N, Si:O and Si:C are provided so that the inherent hardness of the silicon-based light-sensitive layer will not be impaired. These surface layers are effective in solving the aforementioned problems.
However, a photoreceptor provided with a surface layer having the above-described compositions such as Si:N, Si:O and Si:C is not suitable for practical use since if it is put to cyclic use over a prolonged period in a hot and humid atmosphere, it becomes more likely to produce a blurred image.